Third-harmonic generation with a more than 500 nm tunable spectral range in a step-index tellurite fiber

Abstract

We demonstrate third-harmonic generation (THG) with a tunable spectral range of more than 500 nm in a step-index tellurite fiber. Third-harmonic (TH) signals with a peak wavelength from 524 to 1043 nm are obtained in a 3 cm-long fiber when the fundamental wavelength shifts from 1560 to 3100 nm. To our knowledge, the tunable spectral range covering almost one octave is the widest tunable range of THG in fibers so far. The far-field patterns of the TH signals by 1560 nm to 2100 nm pumping are recorded by a charge coupled device camera, which are close to the fundamental mode profile. The THG in such a wide tunable range is attributable to the high nonlinearity of the tellurite fiber and the high pump peak power of the pump pulse.